3 Fraud Transacations in my father sbi debit card

Two transactions has been done from my father account with out my knowledge (OTP was provided by my father as he was unaware of the OTP Process and he provided OTP for only 2 transactions which are transaction 2 and transaction 3. But for transaction 1 there is no otp recieved and sms for debited amount also not recieved). I went to bank and checked with the they are not all responding and there is not bothered at all. And my doubt is how that fraud person knows that my father having SBI card.